# Calculate confidence intervals for grouped values

### Description

`CutCI`

groups values of one variable into intervals with the same number of observations each and computes confidence intervals for the mean of another variable in each interval.

`CIrho`

computes the normal theory confidence interval for a vector of values.

### Usage

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### Arguments

`dat` |
a numerical data frame or matrix with two columns, the first of which gets averaged, and the second of which defines the grouping |

`number` |
the number of equal-count intervals |

`func` |
summary function for computing the mean |

`rho` |
a vector of measurements |

`alpha` |
the desired confidence level |

### Details

The quantiles for the confidence interval are taken from the standard normal distribution, so a reasonable number of observations per interval would be good.

### Value

`CutCI`

returns invisibly a list of length three:

`x` |
the midpoints of the grouping intervals |

`y` |
the means within each interval, as computed by |

`yci` |
a matrix with two columns, giving the lower and upper end of the confidence interval respectively |

`CIrho`

returns a vector of length two, containing the lower and upper end of the confidence interval.

### See Also

`co.intervals`

### Examples

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